The present invention relates generally to power window regulators and more specifically to an apparatus and method for determining the position of a window.
Power windows in automobiles are known to the art. A passenger in a vehicle is capable of raising or lowering a window by pressing a button generally located near a door release for an automobile. The movement of the window is generally controlled through a power window regulator. Power window regulators monitor the position of the glass from the closed position to the completely open position. Further, power window regulators may provide information regarding position of the glass to anti-squeeze controllers. An anti-squeeze controller may stop the movement of the glass if an obstruction is present between the glass and an upper seal.
Power window regulators known to the art fall into one of two types. The first type of power window regulator tracks the glass position continuously. The second type of power window regulator utilizes a sensor to determine if the glass has passed a predefined location usually close to the upper seal. Both types of power window regulators known to the art are subject to problems. For example, the type of power window regulator that tracks the glass position continuously is subject to numerous corrections. Over time, the numerous corrections that are required may lead to serious discrepancies between the actual glass position and the computed glass position. Also, the continuous glass position tracker type of power window regular renders more information than is necessary for typical anti-squeeze controllers.
The power window regulators that utilize a sensor to determine if the glass has passed a defined point is superior than the continuous tracking type, however it is limited by the high price of the item. With the defined point type of power window regulator, the travel path that the glass follows is divided into two regions or states. In the first state, the glass may encounter an obstruction in the path and the movement of the glass may be adjusted accordingly. In the second state, usually one millimeter from the upper seal, the glass may not encounter an obstruction. As stated, power window regulators are costly as a result of requiring a sensor and wires that communicate sensor data to a microcontroller.
It would be advantageous if a power window regulator existed that has the benefits of a two-state position type with regards to ease in use and reliability that may be utilized with anti-squeeze controllers without a requirement of an actual sensor and wires.
Accordingly, the present invention is directed to a novel method and apparatus for sensing whether glass has passed a boundary between the two-state space in which it travels along with the direction of travel by modifying a physical parameter of the motor during operation. Further, the present invention is capable of determining the direction of travel of the window glass without requiring a separate sensor and wires.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles.